<template>
	<view class="u-wrap">
		<view class="u-search-box">
			<u-search placeholder="输入商品搜索" v-model="keyword" @custom="searchGoods" @clear="clearSearch"></u-search>
		</view>
		<view class="u-text-center u-m-t-30">
			<u-tabs :list="sortList" bar-width="100" item-width="150" :is-scroll="false" :current="currentSort"
				@change="changeSort"></u-tabs>
		</view>
		<view class="u-menu-wrap">
			<scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop">
				<view v-for="(item,index) in categories" :key="item.id">
					<view v-for="(c,ci) in item.children" :key="c.id " class="u-tab-item"
						:class="[current == c.id ? 'u-tab-item-active' : '']" :data-current="c.id"
						@tap.stop="swichMenu(c.id)">
						<text class="u-line-1">{{c.name}}</text>
					</view>
				</view>
			</scroll-view>

			<scroll-view scroll-y class="right-box" @scrolltolower="scrollEvent">
				<view class="page-view">
					<view class="class-item">
						<!-- <view class="item-title">
								<text>{{item.name}}</text>
							</view> -->
						<view class="item-container">
							<navigator class="thumb-box u-p-b-40 u-p-t-40" v-for="(goods, goodsIndex) in goodsList"
								:key="goods.id" :url="'/pages/goods/show?id='+goods.id">
								<image class="item-menu-image" :src="goods.cover_url" mode=""></image>
								<view class="item-menu-name">{{goods.title}}</view>
							</navigator>
							<view class=" u-flex-1 u-p-40" v-if="goodsList.length ==0">
								<u-empty text="暂无数据" mode="list"></u-empty>
							</view>
						</view>
					</view>
				</view>
			</scroll-view>

		</view>
	</view>
</template>
<script>
	// import classifyData from '@/common/classify.data.js';
	export default {
		data() {
			return {
				sortList: [{
						name: '默认'
					},
					{
						name: '销量'
					},
					{
						name: '推荐'
					},
					{
						name: '价格'
					},
					{
						name: '评论'
					},
				],
				currentSort: 0,
				categories: [],
				goodsList: [],
				scrollTop: 0, //tab标题的滚动条位置
				current: 0, // 预设当前项的值
				menuHeight: 0, // 左边菜单的高度
				menuItemHeight: 0, // 左边菜单item的高度
				current: 0,
				page: 1, //分页
				keyword: '', //搜索关键字
				isLast: false //是否是最后一页

			}
		},
		onLoad() {
			this.getData();
		},
		computed: {

		},
		methods: {
			// 根据排序重置商品数据
			changeSort(index) {
				this.currentSort = index;
				// 重置商品数据和分页
				this.initData();
			},
			// 获取商品数据
			async getData() {
				const params = {
					page: this.page,
					title: this.keyword,
				}

				// 判断是否有分类ID
				if (this.current) params.category_id = this.current;

				// 判断是否有排序 ，增加排序条件
				if (this.currentSort == 1) params.sales = 1;
				if (this.currentSort == 2) params.recommend = 1;
				if (this.currentSort == 3) params.price = 1;
				if (this.currentSort == 4) params.comments_count = 1;

				const res = await this.$u.api.goodsList(params);
				this.categories = res.categories;
				// 如果用分页，不能直接使用赋值 res.goods.data 修改成如下：
				this.goodsList = [...this.goodsList, ...res.goods.data];
				this.isLast = res.goods.next_page_url ? false : true;
			},
			/**
			 * 搜索商品
			 */
			searchGoods() {
				// 搜索商品，进行重置分类ID
				this.current = 0;
				this.initData();
			},
			/**
			 * 清除搜索商品
			 */
			clearSearch() {
				this.keyword = '';
				this.initData();
			},
			/**
			 * 重置商品和分页
			 */
			initData() {
				this.page = 1;
				this.goodsList = [];
				this.getData();
			},
			/**
			 * 右侧区域滚动到底部，加载下一页
			 */
			scrollEvent(e) {
				if (this.isLast) return;
				// 重新请求数据，单上分页参数
				this.page = this.page + 1;
				this.getData();
			},
			// 点击左边的栏目切换
			async swichMenu(cid) {
				if (cid == this.current) return;
				this.current = cid;
				this.initData();
				// 如果为0，意味着尚未初始化
				// if(this.menuHeight ==0 || this.menuItemHeight ==0){
				// 	await this.getElRect('menu-scroll-view','menuHeight');
				// 	await this.getElRect('u-tab-item','menuItemHeight');
				// }
				// // 将菜单活动item垂直居中
				// this.scrollTop = index = this.menuItemHeight + this.menuItemHeight /2 - this.menuHeight / 2;

			},
			// 获取一个目标元素的高度
			// getElRect(elClass, dataVal) {
			// 	new Promise((resolve, reject) => {
			// 		const query = uni.createSelectorQuery().in(this);
			// 		query.select('.' + elClass).fields({
			// 			size: true
			// 		}, res => {
			// 			// 如果节点尚未生成，res值为null，循环调用执行
			// 			if (!res) {
			// 				setTimeout(() => {
			// 					this.getElRect(elClass);
			// 				}, 10);
			// 				return;
			// 			}
			// 			this[dataVal] = res.height;
			// 			resolve();
			// 		}).exec();
			// 	})
			// },
			// 观测元素相交状态
			// async observer() {
			// 	this.tabbar.map((val, index) => {
			// 		let observer = uni.createIntersectionObserver(this);
			// 		// 检测右边scroll-view的id为itemxx的元素与right-box的相交状态
			// 		// 如果跟.right-box底部相交，就动态设置左边栏目的活动状态
			// 		observer.relativeTo('.right-box', {
			// 			top: 0
			// 		}).observe('#item' + index, res => {
			// 			if (res.intersectionRatio > 0) {
			// 				let id = res.id.substring(4);
			// 				this.leftMenuStatus(id);
			// 			}
			// 		})
			// 	})
			// },
			// 设置左边菜单的滚动状态
			// async leftMenuStatus(index) {
			// 	this.current = index;
			// 	// 如果为0，意味着尚未初始化
			// 	if (this.menuHeight == 0 || this.menuItemHeight == 0) {
			// 		await this.getElRect('menu-scroll-view', 'menuHeight');
			// 		await this.getElRect('u-tab-item', 'menuItemHeight');
			// 	}
			// 	// 将菜单活动item垂直居中
			// 	this.scrollTop = index * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
			// },
			// 获取右边菜单每个item到顶部的距离
			// getMenuItemTop() {
			// 	new Promise(resolve => {
			// 		let selectorQuery = uni.createSelectorQuery();
			// 		selectorQuery.selectAll('.class-item').boundingClientRect((rects) => {
			// 			// 如果节点尚未生成，rects值为[](因为用selectAll，所以返回的是数组)，循环调用执行
			// 			if(!rects.length) {
			// 				setTimeout(() => {
			// 					this.getMenuItemTop();
			// 				}, 10);
			// 				return ;
			// 			}
			// 			rects.forEach((rect) => {
			// 				// 这里减去rects[0].top，是因为第一项顶部可能不是贴到导航栏(比如有个搜索框的情况)
			// 				this.arr.push(rect.top - rects[0].top);
			// 				resolve();
			// 			})
			// 		}).exec()
			// 	})
			// },
			// // 右边菜单滚动
			// async rightScroll(e) {
			// 	this.oldScrollTop = e.detail.scrollTop;
			// 	if(this.arr.length == 0) {
			// 		await this.getMenuItemTop();
			// 	}
			// 	if(this.timer) return ;
			// 	if(!this.menuHeight) {
			// 		await this.getElRect('menu-scroll-view', 'menuHeight');
			// 	}
			// 	setTimeout(() => { // 节流
			// 		this.timer = null;
			// 		// scrollHeight为右边菜单垂直中点位置
			// 		let scrollHeight = e.detail.scrollTop + this.menuHeight / 2;
			// 		for (let i = 0; i < this.arr.length; i++) {
			// 			let height1 = this.arr[i];
			// 			let height2 = this.arr[i + 1];
			// 			// 如果不存在height2，意味着数据循环已经到了最后一个，设置左边菜单为最后一项即可
			// 			if (!height2 || scrollHeight >= height1 && scrollHeight < height2) {
			// 				this.leftMenuStatus(i);
			// 				return ;
			// 			}
			// 		}
			// 	}, 10)
			// }
		}
	}
</script>

<style lang="scss" scoped>
	.u-wrap {
		height: calc(100vh);
		/* #ifdef H5 */
		height: calc(100vh - var(--window-top));
		/* #endif */
		display: flex;
		flex-direction: column;
	}

	.u-search-box {
		padding: 18rpx 30rpx;
	}

	.u-menu-wrap {
		flex: 1;
		display: flex;
		overflow: hidden;
	}

	.u-search-text {
		font-size: 26rpx;
		color: $u-tips-color;
		margin-left: 10rpx;
	}

	.u-tab-view {
		width: 200rpx;
		height: 100%;
	}

	.u-tab-item {
		height: 110rpx;
		background: #f6f6f6;
		box-sizing: border-box;
		display: flex;
		align-items: center;
		justify-content: center;
		font-size: 26rpx;
		color: #444;
		font-weight: 400;
		line-height: 1;
	}

	.u-tab-item-active {
		position: relative;
		color: #000;
		font-size: 30rpx;
		font-weight: 600;
		background: #fff;
	}

	.u-tab-item-active::before {
		content: "";
		position: absolute;
		border-left: 4px solid $u-type-primary;
		height: 32rpx;
		left: 0;
		top: 39rpx;
	}

	.u-tab-view {
		height: 100%;
	}

	.right-box {
		background-color: rgb(250, 250, 250);
	}

	.page-view {
		padding: 16rpx;
	}

	.class-item {
		margin-bottom: 30rpx;
		background-color: #fff;
		padding: 16rpx;
		border-radius: 8rpx;
	}

	.class-item:last-child {
		min-height: 100vh;
	}

	.item-title {
		font-size: 26rpx;
		color: $u-main-color;
		font-weight: bold;
	}

	.item-menu-name {
		font-weight: normal;
		font-size: 24rpx;
		color: $u-main-color;
	}

	.item-container {
		display: flex;
		flex-wrap: wrap;
	}

	.thumb-box {
		width: 50%;
		display: flex;
		align-items: center;
		justify-content: center;
		flex-direction: column;
		margin-top: 20rpx;
	}

	.item-menu-image {
		width: 120rpx;
		height: 120rpx;
	}
</style>
